Process of brightening and hardening electrolytically-tinned articles



LOUIS SCHULTE, OF CHICAGO, ILLINOIS.

PROCESS OF BRIGHTENING AND HARDENING ELECTROLYTICALLY-TINNED ARTICLES.

No Drawing. Application filed July 12,

and useful Improvements in Processes of Brightening and Hardening Electrolytically-Tinned Articles, of which the following is a full, clear, and exact description.

This invention relates to a process of brightening and hardening electrolytically tinned articles.

In the art of electrolytic tinning, it is well known that electrolytic depositions of tin and other metals cannot be produced with a bright or lustrous surface. I have found a method by which such tin deposits can be brightened and hardened at the same time, thereby greatly improving the electrolytic tinning. v

In the preferred form of the invention, I employ a neutral chemical compound having a melting point higher than that of tin. This chemical compound may be ordinary commercial saltpetre which is melted in an iron pot by means of a gas flame or any other suitable heating medium, and in this molten saltpetre I suspend the electrolyticall tinned articles for a few seconds, which pro uces a bright finish and case-hardens the 1 tin to a structure heretofore not known which will impart a long wearing quality to a thin coating of tin.

Some of the saltpetre willadhere to the Specification of Letters Patent.

Patented May 9, 1922.

1920. Serial No. 395,626.

metal articles and this may be removed by dipping same in boiling water and after such boiling water has become saturated with saltpetre, this may be evaporated to leave a residue of saltpetre, which may be used over.

again in the melting pot.

I claim:

1. The herein described process which comprises immersing electrolytically tinned articles in a molten chemical compound having a melting point above that of tin.-

2. The herein described process which comprises immersing electrolytically tinned articles in a neutral molten chemical compound.

3. The herein described process which comprises immersing electrolytically tinned articles in saltpetre.

4. The process of brightening electrolytie cally tinned metal articles, which comprises immersing said articles in molten saltpetre.

. 5. The process of hardening electrolytic tin, which comprises immersing electrolytically tinned articles for a few seconds in molten saltpetre.

6. A process of brightening and hardening electrolytic tin, which comprises immersing the same in molten saltpetre.

The herein described process which comprises immersing electrolytically tinned articles in molten commercial 'saltpetre.'

In testimony that I claim the foregoing l hereunto ailix my signature.

' LOUIS SCHULTE. 

